Coal burner



Sept 2s, 1933.

R. E. BRESSLER COAL BURNER Filed Aug. 11.

' Patented Sept. 26, 1933 UNITED STATES PATEN'I' 'OFFICE 1 Claim.

This invention relates to coal or solid fuel burners of the underfeed type and has for its object to provide a new and improved device of this description.

When coal, for example, is fed to an underfeed retort from below with the re above, the coal is heated and tar is produced, and other more or less volatile ingredients in the coal are partly freed, thereby forming a sticky mass which packs very readily. One of the objects of the present invention is to provide means for preventing the packing of this mass and maintaining a loose mass in the burner.

The invention has as a further object to provide an even distribution of the coal in the burner.

The invention has other objects which are more particularly pointed out in the accompanying description.

Referring now to be drawing, Fig. 1 is a sectional view through one form of the device embodying the invention.

Fig. 2 is a sectional view taken on line 2-2 of Fig. 1, with the retort empty.

Fig. 3 is a sectional view showing construction.

Like numerals refer to like parts throughout the several figures. a

Referring to the drawing, I have illustrated a hopper l in which is placed the fuel to be burned. This hopper delivers the fuel to a feeding screw section 2 disposed in a casing or conduit 3. The screw section is supported on the shaft 8 which is operated in any desired manner, as, for example, bythe motor 4, a speed reducer mechanism 5 being interposed between the motorand the shaft. The screw section 2 conveys the fuel to the underfeed retort comprising the upper tuyre section made up of grate bars 6 with air spaces 'l between them, said tuyre section being supported by an imperforate bottom member or base 'l' between which base and the hopper the conduit 3 extends. The shaft 8 extends through the conduit 3-and the retort base and into a cylindrical pocket projecting outwardly from the base directly opposite and in alignment with the conduit 3. The conveyor screw section 2 is entirely within the duct 3 and the shaft supports another screw section 9 enclosed entirely within the pocket 10, the screw sections being of opposite pitch. With this arrangement the opposed feeding action of the screw sections will uniformly fortet the fuel upwardly into and through the re 55 The disposition of the two screw sections in the a modified manner stated avoids churning and recirculation of the fuel in the retort and causes uniform upward travel of the fuel into and through the retort while the conveyor screw is turning. Should feed of coal from the hopper stop but the shaft continue to rotate, the screw section 2 will convey out of the duct 3 any fuel remaining therein and the screw section 9 will convey out of the pocket l0 any fuel remaining therein and this fuel is fed upwardly into the retort, but thereafter there can be no churning or recirculation of the fuel in the retort by reason of the screw sections 2 and 9 being disposed entirely within the duct 3 and pocket l0 respectively.

In Figure 3 I have shown a modified construc- 70 tion wherein the shaft 8 is provided with a disc 1l and disposed entirely within the pocket or recess 12. The disc may be provided with projections 13 f on its inner face and'will cooperate with the screw section 2 to direct the fuel upwardly into 75 the retort.

With my improved arrangement it is evident that fuel will be directed uniformly upwardly in- 4to and through the retort andpacking of the fuel will be prevented and churning and recirculation of fuel in the retort will be eliminated.

I claim: Y

An underfeed stoker comprising a retort having an upper tuyre section and an imperforate bottom member, a fuel feed conduit extending from said bottom member, said member having a cylindrical pocket projecting outwardly directly opposite and in alignment with said conduit, a fuel hopper communicating with said conduit, a screw conveyor shaft extending through said conduit and retort bottom and terminating within said pocket, said shaft having axially spaced screw sections of opposite pitch thereon, one section being disposed entirely within the conduit 

